Control apparatus for internal-combustion engines



W LEE 1| 2,669,093

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 10, 1947 2 Sheets-Sheet 1 m 28 THEEMAi 4 CONTROL ENGINE on. PRESSURE RA|N (pl) I44 |42 q :38 TO INCREASE P DELIVERY\\ f ,88 uvmuuuc K MOTOR a Z A w (P 96 I06 I08 INVENTOR. LEIGHTON LEE II AGENT Feb. 16, 1954 LEE 2,669,093

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 10, 1947 2 Sheets-Sheet 2 mmo/vsrm f/VG/Nf {DZ/440V Ea 2 248 THERMAL @52 yg m/mmsf 0510 57) /70 FROM SOURCE INVENTOR. [Z /61770 55 I Patented Feb. 16, 1954 CONTROL" PARATUS FOR INTERNAL.-

GOMBUSTION EN GINE S" Leighton--Lee: 'II-,;;Itocky Hill; Gonna assignor -to Nilesl-Bement-BondCompany, West Hartford;- Conn., i a corporation. of :Ne'w J ersey Appncatibneanuary- 10, 1947, Serial Ni). 7215269 1450mm, (c1. lam-39.28).

The present invention applies :torfuel andispeed controltapparatusrfor..primeimovers;:,and particularlyfort internala combustiont engines, inclusive:

of 'gasturbines andicombination'gaseturbineeand jet engines;

The particular embodiments of the. invention-1 showntand described hereimarezinte'nded fori C011?" trolE-of; fuell delivered: to aneintemal combustiom engine;- suitable for jetpropulsionggz propeller propulsion, or combined propeller-and-jetvpro-- pulsioni ofi faircrafite Such-ii an: enginenusually 5-includes a compresson': onev Y or morencombu'st-ion chambers, a: turbine;-= an'd-;a tail'pipe'; inithe stated order of arrangement. 7 Associated with the-em" gineaiisi afuel pump? ion: delivering fuel. to: the: combustion'ichambers andg'gconnected tdtheacomi propellensshaft and- :ertainsae'ces'sories.

The normal; range of engine speed; varieswfrom= aw minimum? value which; approximates'- 8,000 R-.- P; in the particularenginea described here.- in, V to" a correspondingl maximum '01! fullspeed-r value approximating;13,-000 :R-. -P. Me. I. The engine: isi accelerated by external startingameans to the minimum speed, at-rwhioh self-operationoccurs and therexternal means-rceasessto. iunctiom Both speed-and temperature controlvarez cr-i.-. tically important:inuoperation ofq-an internals combustion engine such asrdesoribed, principally; owing to structuraliand metallurgicallimitations of: design. Moreover, the engine speed iis wofl pri mar-y concerrrto' the-operatonsince performance. ofi-aircraft inflightris predicted on the basismof several; factors ofwhich :engine speedtis one Of the more important... I

It is therefore (desirable. to provide fuel liandf speedtcontrol. ap-paratus which enablesrthe'opery. atop-tot regulate :the engine. speed L'asv desired and'l to (render such. apparatus, incapable or delivering'f more .fuel. than...isl required to produce limiting. values off'speed land tem'peratur above which sustained operatibntisjunsafe;

Whilea given-condition of brake-horsepower It is also :an object. of thislinventiomtoipmvidfi in. apparatus Off: the type described improved? meanswfor varying the fuelifflowr te-maintain' a? value of engine speed predetermined;by the posih tion=of a single control leverr Anotherobject ofemyginvention-i-isitos-providev improved :fuel and speed control apparatusflon an internal combustion: engine whereim almamu ally operated i levee is positioned-.= aocerding toi operating conditions in saidvengine -.to-produce a desiredvalue ofspeedz Another I obj ect. of the; present inventionwisetoi provide; in such apparatus, means for controlling? the fuel flowtoprevent speed anditemperaturei values in excess of predetermined limits..

A further objectof myeinvention to providel fueli and speed controli apparatus ofe iinprbved'i simple design which i tends to. minimize hunting} of-the engine; I I I Other objects and advant'agessof Lthe presenfl. inventionwill' become apparentfroma considera; tion. ofthe. appended i specification, claims and drawing, in which: a

Figure liillustrates,somewhat diagrammatical ly,. fuel control "apparatus 'embodvingfiprineiples" of 'my invention. and. the relationship offsu'chi apparatus with an internal combustion" en me and 'a'ssociatedmeans which includetafuelpunip,

and

Figure 2 illustrates; also somewhat diagram?" matically, another embo'di'ment of my invention} and'its relationship withth'e engineofFigure I? Figure-1":

Referring to the drawingiFi'gure lji tl-ier'e"=are*' shown the principal elements-of an internal com bastion" enginesuitable for propelle'fipropul jsion or propeller-'and ietpropulsion? oi' aii er'af has: follows? a supportingca'sing Ifl;-an*"ai l 1 amulti-stage compres'sor indicated a l4, pressor-rotor shaft |6;-a;*combust'ion chambe a number of fuel" diseharge 'noz zl's '-one of which; is designated 20, a generally circular manifolill 22, a"mult'i-'st'age"turbine indicated aS ZWE-a turbine -rotor* shaft 26 connected to the compressor rotor shaft! 6, a tail pip'e -llfi for-discharge of bustion' gases'from-"turbine? center bearingf 3ll' 'and endbearings'izand upportedibwc 5 ing- 'lm a propellershaft fi; andia gear -train 3U connecting'shaft' 36 to -shaft -1 i The fuel m'anifold 22hr the en'gi'neis connected 2' by" a conduit lfl'sto' a" variable :deliverysfuel lpumm 42.1 Pum tziisdriven by the *enginetliruimgeam dl 'andrislfconnected to*a: sourceiofifuelz. y P A inlet conduitM6:;iv Thefi'delivery or variable in responseato movements'nf v which'dsacontrolledz'byr theefiieliandispeectioontibl apparatus, the principal elements of which are identified in the immediately following brief account of its operation.

In the embodiment shown in Figure 1, the speed of an hydraulic motor is maintained at a value proportional to the desired engine speed, the motor speed being controlled by regulating the flow of oil from the engine to the motor along a path including the following elements, in the stated order: an oil supply conduit 48 connected to the engine at a source of oil at a high pres sure (p1) a valve sleeve 86 in a valve mechanism 54, a valve 88, a port I04, a conduit 98, the motor IIJII, a conduit I02, and a drain conduit 5t connected to the engine at a source of oil at a relatively low pressure (p). The position of valve 88 controls the flow of motor oil along the path above defined and is determined by a pressure (pa) in a chamber 94 at the left end of valve 88, the substantially constant value of pressure (p3) being predetermined by the position of a lever 84 in a pressure regulator 66. The pressure in chamber 94 tends to move valve 88 to the right in opposition to a force produced by a speed responsive device I86 operated by motor Iilii, the force produced by said device having a value predetermined by the motor speed and being substantially constant when the motor speed and the pressure in chamber 94 are constant, whereby there is a substantially constant value of the motor speed corresponding to the position of lever 84. A control mechanism H2, connected to the engine and to motor IIJD, detects any difference between the actual engine speed and the desired engine speed as measured by the motor speed, and responds to occurrence of such a difference by moving lever 41 to vary the fuel flow in a sense to restore the actual engine speed to the desired value. The apparatus includes a thermal control I34 which automatically prevents excessive engine temperatures by reducing the speed of motor I 00 whenever a predetermined value of temperature is exceeded. Excessive engine speed is also prevented by limiting the travel of lever 84 and hence the value of the motor speed.

Again referring to Figure l, in detail, oil supply conduit 48 is shown connected across valve mechanism 54 to a conduit 52, thepressurein which is (101) as in conduit 48. Conduits 48 and 52 may be directly connected to each other, if desired.

Another passage for the flow of oil from the engine is provided thru conduit 48, across mechanism 54, and thru conduit 52, a restriction 55 at the lower end of conduit 52, a conduit 58 and another conduit 60 connected thereto, a generally cylindrical'chamber 62 in a body 64 of the pressure regulator 66, and a valve seat 68 in the closed end of body 64 approximately on the centerline of chamber 62, to drain conduit til at pressure (p).

A bellows Ill has one end fixed in chamber 52 to the lower end of body 64 in which there is an aperture I2. On the other end of bellows I0 is a valve i4 operable to vary the effective area of flow thru valve seat 58 in the upper end of body 64. A spring 16, in compression inside bellows between the free end of the bellows and a support I8, tends to move valve 14 upward toward seat 68 with a force which depends on. its initial length and on its rate and deflection. A cam 86, mounted on a shaft 82 is operable by the manually controlled lever 34 to vary the deflection and hence the force of spring 16.

- In operation of the pressure regulator. 66,

fluid enters chamber 62 thru conduit 60 and subjects bellows It! to the differential between the fluid pressure (pa) in chamber 62 and the atmospheric pressure (pa) inside the bellows. The differential (pr-pa), or the gage pressure (113), produces a force proportional to the area of the bellows It in opposition to the force of spring It. Since the position of valve I4 in steady state operation is determined by a condition of balance between forces acting on bellows '10, it follows that, when the position of support I8 is constant, the valve seeks a position at which sufiicient flow is allowed to occur from chamber 62 to conduit 56 to reduce the value of the pressure (p3) so that the upward force of spring 76 balances the down ward force due to the pressure (233) acting on bellows ID. The pressure (:03) is thus maintained substantially constant at a value predetermined by the deflection of spring 16 and hence by the position of lever 84.

The restriction 56 limits the area of flow from conduit 52 so that, as flow past valve I4 increases. the pressure (123) downstream from restriction 56 decreases. The respective areas of restriction 56 and valve seat 68 are such that the regulator 66 operates within acceptable limits of travel of valve 14 and regulates the pressure (1):) within a desired range and with a desirable degree of accuracy.

In valve mechanism 54, valve 88 is slidable in a cylindrical bore 9!) inside sleeve 86, the left-hand end of which is closed and connected to conduit 6i! by a conduit 92. The pressure (pa) is thus transmitted from conduit 60, thru conduit 92, to chamber SM at the left-hand end of valve 88. Valve 88 is provided with an annular undercut 96 which permits flow of fluid from conduit 48, past undercut 96, and thence into conduit 52 and also into conduit 98 and thence thru motor I00 to drain conduit 50. The volume of oil entering' motor I00 and hence the motor speed is a function of the effective area of flow of part I04 to which conduit 98 is connected. The valve 88 is operable to vary the effective area of flow thru port I04 in response to the speed responsive device I86 which is operated by a shaft m3 at the speed of motor Iflfi. If desired, the speed responsive device I96 may be operated at any suitable proportional value of the motor speed.

Device I06 is connected to valve 88 at a groove III provided at the right end of the valve, and moves valve 88 leftward in opposition to the pres sure (21:) in chamber 94, as the speed increases. For any given substantially constant value of the pressure (193), therefore, there is a corresponding substantially constant value of motor speed which produces equilibrium of forces acting on valve 88, and hence positions valve 88 to control the flow thru port I04 and the motor. Assuming substantially constant characteristics of performance of motor IIlB and a substantially constant value of the pressure (p) in conduit I 02, it is apparent that the speed of motor I0!) is predetermined by the value of the pressure (pa) in chamber 94 and conduits 92 and 60.

The lever 84 is operated in reference to a calibrated quadrant, not shown, which enables the operator to visually select the correct lever position corresponding to the value of the pressure (:03) and hence to the respective desired values of the motor and engine speeds.

The condition of equilibrium of forces acting on valve 38, and therefore its position, may be disturbedby increase or decrease of either the motor speed or the value of pressure (pa). Assuming Wltefltirra positibnkof equilibriumrtlie responsetbz' -motor'speed changes may be explainedl ampl lbwsr 1 the-motorspeedtends lac-exceed the predetermined value; va1ve88 movesleftward; the efl-ective area of" flow- 'thru port I G4 is decreased; the motor speed therefore is decreased, and-soul librium is restored at" the" predetermined motor speed corresponding tothevalue of pressure (be).

(2)- S-imilarly', when" the-speed of motor we tends todrop below" the predetermined value, valve 88 is moved toward' the extreme position si'i'ownin-thedi'a-wing; at-

theefiectite area offlbwthru port W4- ismaximuma sewer-im proximately-upon reaching sueh a position, hoveever; the flow thru port PM Will have beerrci'ently' increased to increase the speed er motor i ll'fl andhencerestore thespeedto'the*desiredpredetermined value:

(3) When the pressure- (-p3-)'- is changed bymovement' of the-lever M, a temporary cen'dition follows during which valve 8 3- seeks a new positi'orr ofequilibrium" and thespeed ofmotor H39 changes to' another substantially constant predetermined lesser or greater'value; depending on whether the pressure" (m) is decreased or ill creased'i Ceunterclockwise movement of lever M fromthe position shown increasesthe" motor speed;

Motor' lflil isconnected-by a shaft ll-Otbt controlmechanism* H2 which includes a sun gear Ht" mountedon' and drivenby shaft I It which rotates a clocIiw-isedirection; Gear H4 engages a' similarplanet gear" Ht mounted on astub shaft H8, gear Ht being engaged witha ring gear I20 mounted on a shaft' I22" and: operated by the engine at'a speed proportional'toenginespeed; in a counterclockwisedirection: Bb'tl'i'shaft l-22' and shaft H have'fixed centerlihes. Witha slight increasein the respective" diameters of gears l and" I' I6, thecenterline of shaft l'i fl may be-made to coincide with that of shaft" FZZ accOrdiIIg to conventional practice indiiierentialgearing; separation oftheshaft centerli'n'es, as shown, is permitted-as aresult of the-relativelysrnal'l move ment' of a-lever [242 which holds gears H4 and H6" in proper relationship with each other and in' which shaft H Bis-fixed. Lever I24 is' 'h-ing'ed to' The relative sizes of gears and H4 are selected so that when the actual engine'speed; in dicat'ed'by the sp'eedof" counterclockwise rotation of gear I20; is equal to the desiredengine speed, indicated by the speed of clockwise rotation of gear l"l'4; the tooth velocitiesof gearsil l and F20 are" equal; The ratio" of the" desirecl eng-ine' speed to the motorfsp'e'ed, or to the speedoff rotation of gear H4, ,tlierefore' differs from". the ratio; of the; actual engine. speed" to the speedori rotation of gear IZDL according to the ratio of the respective numbers. of "teethih gears. H41 and 170i In, a con.- dition inwhichthe actual engine. speedequalsthe desiredengine; speed, .orv inwhich the tooth veloci tiesnof gears i Mr and. [211, are equal, ,the :centerlineot shaft H fliandihence lever i243 remains station ary whilew gear' I I firotateson Shanna Among otherx possible: arrangements: of; gears which are. alternate to the :arrangement shown; there isincluded' an assembly of three bevel; gears-- having: aniidentica'l; numbers" of teeth in eacli. Im suclnarr assembly: the ratio; between the? motor speedandithe; speed of; rotation: of a -bevel; gear correspondington gear? lim t is identical. wide-thee.

ratio between the actual engin'e ainilttlie speed? ofiathtien-bfia Bevelfgearrcmespondingztor gear NIL When the actualt speed: exceeds a desiredi' valii'e; 'or' wl ien theztooth velocity" of gear: I? 0:

are caused to: move in: a counterclofckwise direc tion relative tcr-tlie: center of! shaft H0; thereby: movinglever" r24": towardsii stop I 26; A link I'M- connect's sliaft I 18? to lever f so thatasz'l'ever I24 v moves" toward stop I25; lever' llimoves clockwise to decrease tfiedelivery-of pump r 42; The enginespeed? is consequently reduced? until the. desired value-is restored} lever f2 i thentoccupyinga new position between stops: i263 and'. I28 depending upon the amount of! movement of lever 47" required'" to accomp'l ish tl'fefifuel: delivery'decreasei Similarly; wlien'the actual engine speed is less than a desired" value; or when" the tooth velocity of gear l'ZB' less than that of gear H4} gear H6 and shaft*-l l8 arecausedto move ina clockwise direction relative to the centerofshai't H 0;th'ere by movi'ng lever l z l towardsstoo I 28. Lever 4T1 is correspondingly moved counterclockwise" to crease =the deliveryofpump 42?. The engine speed:

isconsequently'increased until the desired valueis restored, lever I24 then occupying a new posi tio'n between sto'ps I25 and I28 depending upon the" amount or movement of lever 47 required to: accomplish the fuel" delivery decrease.

maximum mini'mumpump delivery'set tings determined by extreme positions of lever: 32 lever [25* justcl'ars stops i223 and I26, respectively, and the fuel pump: delivery varying means is correspondingly positioned for maximum and minimumdelivery;

When the actual engine speed deviates from the'd'esired valiiepredeterminedi by the speedof motor Hill-,- so' thatth'e' tooth velocity of gear [2tv diners fi'omthat or gear PM to suchan. extent that lever I'Mmoves againststop liifi or'ltfi', the engine is then direct-eonne'cteditothe motor thru, gears I 20, HG -and lil l. If lever IZ E- is against stop E26, as is the case when the engine speed is greater than desired-,- motor wil is driven by the engine at a speed greater than that corresponding to' the position of lever Thiscon di-tiorrimpeses"nohardship onthe motorfor other. elements of the apparatus; however, andis temporary.

With lever li i-against-stop I25, the fuelpump delivery'has amini'mum-value which quickly'reduee's theen'gine speed and permits restoration of the-desired speed: at: which: lever E 211* is moved off stop I25: Similarly; if lever IE4 is against step ["283 as is the-ease when the engine speed is less'than desired; the engine temporarilydecreases theniotor'speedl Inthis case, however, with lever'againststop 231 the fuel'pump deliveryf has a n'raximum value which quickly increases" the enginespeed, tl iereby' restoring the desired. speed-at" which lever fl t-is movertoff" stop= 1-28.

Thermal control" 134* is provided to protect the engine" against the; possibility of I excessive operatingftemperatures; control-' I t' l being eii'ective to reduce pressure (pr) and hence the motor speed when a predetermined value of temperature is exceeded. Thus, following such reduct'ion".o'ii'imotorspeed,- there 'is a? corresponding recluction of: engine speed. produced by fuelv flow decrease which restores. the engine temperaturetcrsaie operatingivalues.-;

:hermaltcontr: lq3tziconrprisesei bo;dy-"i3tI'ha-v in aewall li3fliseparating=lamoutlet chamber? :41};- treni am iniet chanrbeii M2; Inlet chamber I42:

is connected to conduit 60 and outlet chamber I40 is connected to drain conduit 50 by a conduit I54. One end of a thin-walled tube I44 is fixed to the closed end of body I36 nearest inlet chamber I42, and has attached to its other end, which is closed, a rod I46 which is slidable in a centrally located aperture I48 in the end of body I36 to which tube I44 is fixed. The free end of rod I46 is contoured to form a valve I50, which is operable in a seat I52 in wall I3-8. Tube I44 and rod I46 are made from materials having substantially different coefiicients of thermal expansion and the unit is installed in the engine, as shown diagrammatically, with tube I44 exposed to the temperature of combustion gases in the tail pipe 28 of the engine, or at any other desired control point. As the temperature increases, the tube I44 expands faster than the rod I46, thereby increasing the effective area of opening between valve I50 and seat I52. Generally, control I34 is made so that the valve remains closed until a limiting value of temperature is exceeded.

When valve I50 is closed, as is normally true, no flow occurs in thermal control I34 and the pressure (103) is a function solely of movement of lever 04.

When valve I50 is open, however, as is the case when the predetermined value of limiting temperature is exceeded, flow occurs thru conduit 60, chamber I42, past valve I50, thru chamber 40, and thence thru conduit I54 to drain conduit 50. As valve I56 opens to permit such flow, the pressure (133) in conduit 60 decreases owing to in creased flow thru restriction 50. The speed of motor I consequently decreases, the fuel flow decreases to provide a corresponding engine speed decrease and the engine temperature is thereby reduced. Valve I50 is restored to closed position and the pressure (103) is restored to its normal value when the engine temperature equals or falls below the predetermined limiting value. Normal operation of the apparatus is then reestablished.

Protection of the engine from over-speeding is provided by limiting the travel of lever 84. There is thus a maximum value of the pressure (213) and hence maximum predetermined values of the motor and the engine speeds.

In steady state operation, engine speed deviations from the desired value determined by the speed of motor I00 generally occur slowly and are of small magnitude. The response of gear I20 to changes in engine speed is immediate and, similarly. the response of lever I24 and hence of the delivery varying means to such variations in engine speed is also immediate. Time lag, therefore, between demand for a change of fuel flow and the occurrence of such change is of sufficiently small proportions to prevent hunting. Upon rapid movement of control lever 04, the consequent change of motor speed is not equally rapid owing to inertia of the motor and to the time required for change of the rate of .flow thru valve 88. The delivery varying means,.however, immediately responds to changes in the motor speed so that hunting inthis case is also pre-. vented.

Figure 2 Referring to the drawing, Figure 2, there is shown another embodiment of my invention connected to the diagrammatically illustrated engine of Figure l. A variable delivery fuel pump I50, driven by the engine or other suitable means thru -a gear I60, is connected to an indicated source of fuel by a conduit I62 and to manifold 22 of the engine by a conduit I64. The delivery of pump I58 is variable in response to movement of a lever I66 which is controlled by the fuel and speed control apparatus between extreme counterclockwise and clockwise position correspond ing to minimum and maximum fuel flow and em gine speed.

Principal elements of the apparatus include a differential gear mechanism I68, a governor valve mechanism I10, a thermal control I34 the same as or equivalent to the control I34 of "Figure 1, and an hydraulic motor I12.

The differential gear mechanism I68 includes: a segmental gear I14 rotatable thru a predetermined arc on a fixed shaft I16, there being a manually operated control lever I18 fixed to gear I14; a sun gear I rotatable on fixed shaft I16;

an arm I82 fixed to sun gear I00 and connected to lever I66 by a link I84 so that the delivery vary ing means is responsive to rotation of the sun gear; a planet gear I86 rotatable on a stub shaft I83 for transmitting movement of segmental gear I14 to sun gear I60; a link I00 connecting shafts I16 and I86 for allowing shaft. I88 to be moved about shaft I10 as a center; and a link I92 connected to shaft I08 and the left end of a lever I94 which has its right-hand end fixed to a shaft I06. The shaft I96 is rotatable in response to movement of a worm gear 200 fixed to shaft I96 and in engagement with a worm gear 200 fixed to shaft I and in engagement with a worm I98 on a shaft 202. Self-locking action of the worm and worm gear prevents rotation of shaft 202 in response to movement of lever i84 and shaft I96.

Governor valve mechanism I10 includes a speed responsive device 204 operated by gearing 206 which is driven at a speed proportional to engine speed. A valve 208 is slidably operated by device 204 in a valve guide 2I0. Valve 208 has an undercut 2I2 forming an annular chamber 2I4 between valve 208 and guide 250. Between the respective right-hand ends of valve 208 and guide 2I0 there is a chamber 2H5 connected to annular chamber 2I4 by a channel ZIB. A port 220 in guide 2I0 is connected to a source of oilat a substantially constant pressure (111) by conduit I64, as in Figure 1; and another port 222 is similarly connected to a source of oil at a relatively low pressure (p) by means of conduit I65, also as in Figure 1. Any other hydraulic fluid source providing a suitable value of the difierential (p1p) may be employed if desired.

In the neutral position of valve 203 shown, both ports 220 and 222 are just closed. When valve 208 is moved to the right from its neutral position, oil may flow from conduit 553, thru port 220, chamber 2I4, and channel 2I6, to chamber 2I6. correspondingly, when valve 208 is moved leftward from its neutral position, oil may flow from chamber 2I6, thru channel 2I8, chamber 2I4, and port 222, to conduit I65. The valve is subject to opposite forces produced b device 204 and the pressure (204) in chamber 2I6 and is in equilibrium when these forces'are equal, the value of pressure (:04) therefore being determined by the value of engine speed. It is thus apparent that in a condition of equilibrium, valve 208 is in its neutral position, no flow occurs past the valve, the engine speed is constant corresponding to a steady state condition of engine operation, and pressure (274) is substantially constant and has a value corresponding to the value of the engine speed.

iflhe'divdraulicimotord 'tmncludes a-ihousingml rhored. forioperiation -:of piston iflfiitherein. in schamber zzcwabove piston iis'lconneflted to ichamher 2 1:6 rthru.arconduit 1.24.0 so that ressure 1(4),.4) is transmitted =to-zchamber i223. A-% hamher 238 below piston 226 is connected'itovoonduitI64 chm (a-conduit :2 30 ,a restriction-23 i,zandwanother conduit 12-36. subsequently :explained, :dufipg i-normalro'peration, there :15 :no'fiow thru restriction i234 :sontha-t the pressure :(qn) :in-conduit I64 is thermally transmitted along the above defined path toichamber flfifl; Thus, piston 22% .is ,norimallysubject to an upward force proportional .to the pressure differential imp- 114) {which varies miversely r-asrthe'enginespeed; tire, (QM-11M) has a .maximum value when the avalue of enginespeed v.is :minimum, .and .p1 pi') has -a minimum value when -the value of engine speed is maximum. *PiStOH 2-26-is biasedidownward' by azspringizfl .hut ,r-emains in its extreme upward position :until .theiengine 'speed increases :to :a predetermined \valueand the {pressure differential (pi-m4) .de- .creases so that the downward spring force exioeeds :the upward force of the. differential. When a-thls occurs, gpiston 226 moves .downward and is .iman extreme downward position when the en- ;gine speed :exceeds :a preselected limiting value.

.Piston 226 is connected to a :lever 2 3 i fixed (to shaft-filthy zmeans 10f .-a .rod 246, so that when ;;piston ZZS-isdn itsextreme upward and downward ,p'ositions, respectively, .shaft 262 is at corresponding extreme limits-of counterclockwise and clockwise rotation.

Hihe thermal control shown diagrammatically inrFigureifirexactlyi corresponds to its counterpart zini'Eigurel andihasibeeng-givenrthe-same ref-er- .enoe numeral I36. It willanothe described in :detail tin connection with -=the present figure. 'fl hermal control/1:34 eonnectedltorconduit 4230 dayan inlet conduit: 232 correspondingmo .thecon- .49

.nectionof :the thermal control of figure 1 with ---.conduit60. Similarly,.-a conduit 2.43, corresponding .to zconduit i 4 ;of .iiigure .1, connects the athermal control to-drain conduit I155. As ex- ;plained -in connectiomwith :Figure *1, ea portion -:.of.'the1contro1 4:34 is subjected .to :the engine temperature and prevents flow from conduit 232 to conduit -246 at;.normal=-engine temperatures. iWhen'the engine temperature-exceedsia predetermined limiting value, however, z-the thermal' control allows flow to occur fromaconduit 232;, thru jtthe thermalrcontrol to conduit Z48 -Ihe.-consexquent flow through'restriction 234, is accompanied .by: a,pressure drop iniconduit 12130 :and 3' chamber 1&8. The apparatus is designed: and constructed .so that how occurring at. "an excessive engine temperature; produces a sufficient drop in value f? the: pressure; in chamberi238, so? that; piston :22 6 moves downward tolits extreme position.

:Itiis thus: apparent: that when the engineaspeed1== ,levers 4.82 and I 6.6 depend .upomthatof manually .operated lever 4.1.8. YIn -normal operation, the

differential gear mechanism serves only to vary tl'lQyDOSitiOIlvOf lever 4,6,6 and ,hence to vary the 5 fuelflow-as-a iunction ofrmovementof lever I18, there :being apredetermined position of lever I66, and therefore a predetermined value of fuel flow, for every position ofithe manually operated lever I-TB. v

When lever I'ld is moved counterclockwise frornxthe position shown, withshaft I96 fixed as in normal ioperation, planet :gear I86 is rotated counterclockwise -on-shaft L88,-and sungear I is correspondingly rotated .inra clockwise direcitionzcausing lever {I82 ia-nd-link I84 tooperate lever 66 in a delivery increasing direction. Conversely, when lever glflfiriszrotated clockwise, planet sear Hi6 :also rotates clockwise, and sun gear i'86 turns in ,-a counterclockwise direction to operate lever 466 in :a delivery decreasing 1-direction.

Assuming that the position of lever I66 is fixed-and'that the engine isroperating at a speed less than the limiting value; when the engine speed changeaowing to a changeinengine operating-conditions, :the pressure 1104) in chamber 2I6-and-228changes, butrthere is no movement of piston 2'26 and henceno-change of fuel flow until the speed :loecomesexcessive; i. e., until the speed exceeds the ;predetermined limiting value. When this occurs,,piston.2-26 is: moved downward as previously explained so ,that shaft 2% is .moved to an extremeicounterclockwise position. Counterclockwise rmovement of shaft 262 and hence of worm #98 causes counterclockwise movement of worm gear 7200 and shaft I96. Upon counterclockwise movement of shaft I and lever I94, link I82 moves downward, and shaft iiiS-movesinacircular path in a counterclockwise directiomaround shaft I76 as a center, causing planet gear I86 to rotate clockwise on shaft I88 because of its engagement with ring gear I14. Sun-gear IBD is rotated counterclockwise by gear I86, thereby-moving lever I82, link I84, and lever I;66-in-a delivery decreasing direction. .As the-delivery decreases the-engine speed .decreases,;pressure (124) decreases andwhen the @speediis less than thepredetermined value, .piston 226 rises :to=.the :normal position correspondingto -the;normal.,position of shaft I96. In this manner, manual regulation of the pump delivery and :hencemanual:regulation of engine speed is subjechtoioverridby the. governor valve mechanismz-Ilfl and motor I72. The amount of .overrideicontrol is-such that when lever we is fixed .inzits extreme counterclockwise position, corresponding-to maximum pump delivery, movement :of :piston 2261mm its normal position to its extreme downward positioncauses movement of 5 lever 166 .to :a position corresponding to mini- .mum delivery;

:Responsemf the apparatus to engine tempera- -.tures:exceedingLthenpredetermined limiting value -isidentical-withthat in thecase of over speeding after .thei pressureiin. chamber 235i; is sufficientlyreducedito cause movement of pistonZZEi to its. extreme downward position.

.Useof the controlappar-atusof Figure 2 .requires.manipulationoithe controllever H 6 into :70 whatever positionds rcquiredto obtain a desired value ef speediindicated'hy .a tachometer 256 or equivalent-speed indicatingdevice. As the en- .gine .speed varies the .operator readjusts v the lever position ",tO maintain'.,the desired value of sand-shaft I88+are alsofixed and the, positions .ofnm speed.

In the apparatus of Figure 2, response of the delivery varying means to movement of control lever I80 is immediate. Similarly, response of device 204 to changes in engine speed is also immediate; hunting of the engine is therefore prevented by the absence of time lag between demand for a change of fuel flow and the occurrence of such a change.

The terms and expressions herein are employed for purposes of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

I claim as my invention:

1. Control apparatus for a pump having means for varying the delivery thereof, there being operatively associated with said pump a rotating device whose speed is responsive to said pump delivery, comprising: a manually operated lever, a control lever connected to said delivery varying means for control thereof; and a differential gear mechanism including first and second posi-t tionally movable gears positionally responsive respectively to the speed of said device and to said manually operated lever, and a third gear responsive to the differential movement of said first and second gears and connected to said con-1 U trol lever for actuating said control lever.

2. Control apparatus for a pump having means for varying the delivery thereof, there being operatively associated with said pump a rotating mechanism whose speed is responsive to saidz'; pump delivery, comprising: a manually operated lever, a control lever connected to said delivery varying means for control thereof; and a difierential gear mechanism including first and second positionally movable gears positionally I'd-1 speed is responsive to said pump delivery, coma prising: a differential gear mechanism including a segmental ring gear having a fixed shaft at the center thereof and being manually rotatable on said fixed shaft, a sun gear rotatable on said fixed shaft and adapted to control said delivery varying means as a function of the rotation of said sun gear, and a planet gear for transmitting movement of said ring gear to said sun gear, a stub shaft for rotation of said planet gear thereon, a connecting link between said fixed and said stub shafts for maintaining a predetermined distance between the respective centers of said shafts, and operating means for rotating said connecting link on said fixed shaft to control the rotation of said sun gear and hence said delivery varying means independently of movement of said ring gear, whereby said delivery is a function of the manual operation of said ring gear and the operation of said operating means.

4. Control apparatus as set forth in claim 3, including means responsive to the speed of said device for controlling said operating means, whereby said delivery is a function of the manual operation of said ring gear and the speed of said device.

5. Control apparatus as set forth in claim 3,

including means responsive to the speed of said device and adapted when said speed exceeds a predetermined value to actuate said operating means in a sense to restore said predetermined value of speed.

6. Control apparatus as set forth in claim 3, including a governor mechanism responsive to the speed of said device and adapted to control said operating means, and means responsive to an operating temperature in said speed device for overriding said governor mechanism to actuate said operating means when a predetermined value of said temperature is exceeded.

'7. Control apparatus as set forth in claim 3, including a source of hydraulic fluid and a conduit for the flow of fluid from said source, governor valve means having a valve therein responsive to said speed of said device, said valve being adapted to control the pressure downstream from a portion of said conduit as a function of said speed, and motor means responsive to said downstream pressure in said conduit portion and adapted to control said operating means.

8. Control apparatus as set forth in claim 3, including a source of hydraulic fluid and a conduit for the flow of fluid from said source, a valve for controlling said conduit flow to regulate a pressure downstream from a portion of said valve, channel means for subjecting one end of said valve to said downstream pressure, said valve having a neutral position thereof wherein the value of said conduit flow is substantially zero and said downstream pressure is substantially constant, means responsive to said speed of said device, said valve being responsive to said last means in opposition to said downstream pressure thereby rendering said downstream pressure a predetermined function of said speed when said valve is in its neutral position, said operating means being responsive to said downstream pres sure; and said valve being adapted, when said speed exceeds a predetermined value to vary said downstream pressure and hence to actuate said operating means and said delivery varying means in a sense to restore said predetermined value of speed.

9. Fuel and speed control apparatus for an internal combustion engine having a pump with means for varying the delivery of fuel to said engine, comprising: a source of hydraulic fluid and a conduit for the flow of fluid from said source, a valve for controlling said conduit flow to regulate a pressure downstream from a portion of said valve, channel means for subjecting one end of said valve to said downstream pressure, and a device responsive to the speed of said engine, said valve being responsive to said device in opposition to a force proportional to said downstream pressure and having a neutral position thereof wherein said downstream pressure has a substantially constant value corresponding to a substantially constant value of said speed, control means for operating said delivery varying means in response to said downstream pressure; said valve being adapted, when said speed exceeds a predetermined limiting value, to move from said neutral position in a sense to vary said downstream pressure to restore said predetermined value of speed and to return said valve to said nuetral position.

10. Fuel and speed control apparatus as set forth in claim 9, including a thermal control for modifying the response of said control means in a sense to decrease said delivery independently of 13 7 said downstream pressure when a predetermined value of engine temperature is exceeded.

11. Fuel and speed control apparatus for an internal combustion engine having a pump for delivering fuel thereto, comprising: a differential gear mechanism including a fixed shaft and a segmental ring gear rotatable thereon, a manually operated control lever for rotating said ring gear, a sun gear rotatable on said fixed shaft for operation of said delivery varying means, a stub shaft and a planet gear rotatable thereon for operation of said sun gear by said ring gear, a connecting link between said fixed and said stub shafts for maintaining a predetermined distance between the respective centers of said shafts, control means for varying the angular position of said connecting link to vary the position of said stub shaft, said control means being operable to modify rotation of said sun gear in response to movement of said ring gear and being similarly opersaid speed and temperature responsive means being adapted when said speed and/or said temperature exceed predetermined values to operate said control means in a sense to reduce said delivery, whereby the fuel flow to said engine is a function of the position of said control lever and said speed and said temperature.

12. Control apparatus for an internal combustion engine having a pump for delivering fuel thereto, said pump having means for varying its delivery, comprising: a manually operated control lever, adapted to be moved to a selected position corresponding to a desired engine speed, a control arm connected to said delivery-varying means and adjustable means connected between said lever and said arm, said arm being variably responsive to the movement of said lever; and means responsive to the actual speed of the engine and to the movement of said arm for adjusting said adjustable means, so as to modify the movement of said arm in response to the movement of said lever, in proportion to any difference between actual engine speed and the desired engine speed corresponding to the position of said lever, whereby the fuel delivery of said pump is so controlled as to cause the actual speed of the engine to correspond to the selected desired speed.

13. Fuel and speed control apparatus for an internal combustion engine having a pump for supplying fuel thereto, said pump having movable means for varying the delivery of fuel to control the speed of said engine, comprising: a manual control lever, first means, responsive to said lever, for positioning said delivery-varying means so as to cause said engine to operate at a selected speed, second means responsive to the actual speed of the engine and operatively associated with said delivery-varying means, and third means operatively associated with said first and second means and adapted, when the ratio between said selected and actual engine speeds deviates from a predetermined value, to operate said delivery-varying means in a sense to eliminate said deviation and thereb restore said speed ratio to said predetermined value, whereby said engine is caused to operate at said selected speed under varying operating conditions.

14. Speed control apparatus for a prime mover having means for supplying thereto a motive fluid for operating said prime mover, comprising: means for regulating the flow of said fluid to said prime mover, a servomotor operatively connected to said regulating means, a separate source of liquid under pressure, a conduit for supplying said liquid to said motor, a valve in said conduit for controlling the flow of said liquid to said motor, and. a mechanical centrifugal governor, driven by and solely responsive to the speed of said prime mover, for operating said valve in accordance with said speed, so that said speed is automatically maintained at a constant value under varying loads; the pressure in said conduit between said valve and said servomotor exerting on said valve an axial thrust which is opposed by said governor thrust, whereby the position of said valve is varied in accordance with the dif ference between said thrusts.

LEIGHTON LEE II.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,483,536 Warren Feb, 12, 1924 1,644,167 Best Oct. 4, 1927 1,752,135 Wiinsch Mar. 25, 1930 2,069,230 Ferris Feb. 2, 1937 2,136,959 Winfield Nov. 15, 1938 2,198,035 Ferris Apr. 23, 1940 2,219,994 Jung Oct. 29, 1940 2,245,562 Becker June 17, 1941 2,399,685 McCoy May 7, 1946 2,405,888 Holley Aug. 13, 1946 2,411,065 Silvester Nov. 12, 1946 2,514,674 Schorn July 11, 1950 

